ABSTRACT This Alzheimer?s-focused supplement will investigate the effects of home-based, remotely supervised transcranial direct current stimulation (tDCS) for pain management in persons with Alzheimer's disease (AD). The research proposed in this supplement aligns with the parent study (R15NR018050). The long-term goal of this supplement study is to improve pain management using home-based nonpharmacological approaches. AD is the most prevalent type of dementia, affecting 5.5 million individuals in the United States, and the management of pain is challenging because existing pharmacological approaches often produce significant adverse effects (e.g., constipation, confusion, behavioral disorders, psychomotor retardation, and falls). Also, recent evidence suggests that alterations in pain-related brain mechanisms may contribute to chronic pain. Therefore, innovative nonpharmacological interventions targeting pain-related brain function in persons with AD are needed. One promising pain treatment is tDCS with the anode over the primary motor cortex (M1) and the cathode over the contralateral supraorbital area (SO), as it can change brain activity in a noninvasive, painless, and safe way. tDCS is categorized by the FDA as a ?non-significant risk? device. Moreover, home- based tDCS has been safely used to improve cognitive or memory problems among persons with AD and other dementias. However, no investigations to date have examined whether home-based tDCS can reduce pain. Home-based interventions are critical because persons with AD have difficulty attending clinic-based sessions over several days, and recent technological advances have created the potential for home interventions with real-time monitoring through a secure videoconferencing platform. The central hypothesis is that home-based, remotely supervised tDCS will decrease pain. This hypothesis will be tested by pursuing the following specific aims: evaluate the preliminary effects of home-based M1-SO applied tDCS on clinical pain in persons with early-stage AD (specific aim 1); evaluate the preliminary effects of home-based M1-SO applied tDCS on pain-related cortical response in persons with early-stage AD (specific aim 2); and evaluate the feasibility and acceptability of home-based M1-SO?applied tDCS for pain management in persons with early- stage AD (specific aim 3). We will also obtain data, as an exploratory aim, to investigate whether tDCS reduces behavioral and psychological symptoms of dementia. The proposed study will directly investigate the effects of home-based, remotely supervised tDCS in 40 persons with AD using an experimenter- and participant-blinded, randomized, sham-controlled, parallel group (1:1 for two groups) pilot clinical trial. Caregivers will set up and administer tDCS for persons with AD at home, and participants will be remotely supervised by trained research staff at each stimulation to ensure the use of proper technique. The proposed research is significant because it is expected to provide valuable insight into an exciting new modality of nonpharmacological pain management that is easy, safe, and noninvasive with minimal side effects.